Sanding drum



March 5, 1940. J. o. scHuL'rE SANDING DRUM Filed July 5, 1958 2Sheets-Sheet 2 f fw ATTORNEYS Patented Mar. 5, 1940 UNITED STATES PATENTOFFICE SANDING DRUM John 0. Schulte, Cincinnati, Ohio Application July5, 1938, Serial No. 217,331

3 Claims.

This invention relates to a sanding drum comprising generally a drummember having sanding material in strip form stretched over its workingsurface, the said material being renewed from time to time as it becomesineffective 'from use.

An object of the invention is to provide a sanding drum of this kindhaving novel means for stretching and combining the sanding material onthe working surface of the drum.

Another object is to provide a device of this kind which carriesinteriorly thereof a supply of the sanding material for immediatelyreplenish ing that which has been worn out on the surface of the drum.

Another object is to provide a sanding drum in which it is possible toutilize the complete length of sanding material, substantiallyelimihating waste of any portions of the said material.

Another object is to provide a sanding wheel or drum of simple andeffective construction and use.

Another object is to provide a novel method of properly positioningsanding material on a drum or" the character herein contemplated.

These and other` objects are attained by the means described herein andillustrated in the accompanying drawings, in which:

Fig. 1 is a side view, half in cross-section and half in elevation, of asanding drum comprising the means of the present invention.

Fig. 2 is a view taken substantially on the line 2--2 of Fig. 1, aportion of a tightening tool being shown in association with the figure.

Fig. 3 is a view taken substantially on the line 3--3 of Fig. 1, withparts omitted,

Fig. 4 is a side elevational view, with parts broken away, of a sandingdrum of this invention, showing in association therewith a tool forpositioning sanding material initially on the drum, parts of the drumbeing broken away to disclose the construction.

Fig. 5 is a perspective View of the wedge member forming a part of thepresent invention.

In devices such as sanding drums, polishing wheels and the like, withwhich the present invention is concerned, it is essential that thesanding material be maintained in tight and operative relationship withthe working surface of the drum. Various means have been employed in thepast in the endeavor to secure this essential relationship. In someinstances, a plurality of slots are provided on the drum into which thesanding material is forced and bound by some type of wedge member. Inother instances, it

has been attempted to achieve the tightening action on the sandingmaterial by spring or other pressure means on the interior of the drumand operating on the opposite ends of the sanding material. However, dueto the constant pressure and friction exerted on a sanding wheel duringits use, the means for holding the sanding mate rial in operativeposition have proven ineffective toa greater or less degree.

The present invention provides means for positively binding the sandingmaterial on the working surface of the drum by the use of slots providedin said surface and having portions of the sanding material doubledthereinto and a novel type of wedge member operating, not against theinterior of the slots of the wheel, but against the interior surface orwall of the chamber provided in the drum of this invention, such wedgemember binding the inwardly projecting ends of said doubled portions ofthe sanding material into a secure and non-slipping relation.

In addition to the foregoing, the present invention eliminates waste ofthe sanding material by providing for use of the doubled-in portions ofthe sanding strip on the surface of the drum, subsequent to use of theseportions in the slots of the drum, for binding the material to the drum.

In greater detail and with reference to the drawings, a device of theinvention comprises a rim ID formed of suitable material, such asaluminum, and having secured to its surface a depth of material II, suchas rubber or like compos-1'.- tion, adapted to resist slipping of thesanding material subsequently disposed thereon.

Slots I2 extend from the exterior surface of the material II through therim II) and communicate with a chamber formed in the interior of thedrum. As seen in Fig. 3, the slots of the rim I0 may be closed at theirends, as indicated at I3, while the slots in. the material I I. may beopen at both ends, as indicated at I4.

The sides of the drum are formed by a pair of plates I5 and I5 which,together with the rim lil, form the interior chamber of the drumpreviously referred to. The plates I 5 and I6, as seen in Fig. 2, mayextend outwardly as far as the outer edge of the rim IB. The said platesare centrally apertured for rotatably receiving the core I1, said corebeing hollow or tubular for reception upon a drive shaft I8 normallyassociated with a motor, shown fragmentally at I9.

As seen in Fig. 1, the core Il has a suitable clamping device 2Dassociated therewith for attaching the inner end of the sanding materialto the core, as will be further described.

The plate I5 forms the exterior portion of a wedge member, said platehaving secured thereto, or formed integrally therewith, the wedge bars2| which project inwardly of the drum, transversely of the chamberthereof, and in proximity with the inner wall of the rim I 0. The wedgemember, including the p-late I5 and wedge bars 2l, is shown separatelyin Fig. 5. There it will be seen that the wedge bars 2| are preferablyconvex on their outer surfaces and tapered towards their vertical edgesfor performing the wedging action to be later described.

Figs. l and 2 show a supply of sanding material in strip form wound uponthe core I'I, the supply of material being indicated at 22. Tooperatively associate the material with the core, the normal method isto insert the core Il through the center of the roll of material,thereafter introducing the outer end of the material 22 through one ofthe slots I2 of the drum, the plates I5 and I 6 being thereafterpositioned for closing the sides of the drum. A length of the material22 is withdrawn through the slot and the material carried around theworking surface of the drum. The process of lapping or doubling thesanding material into the slots is illustrated in Fig. 4. A tool 23 isutilized for this inserting process. The tool may comprise a blade orplate member 24, the blade being of such length as to project into theinterior chamber of the drum member a substantial distance beyond therim IU. The sanding material, having been carried to the next slot onthe drum surface. is now doubled into this slot by means of the tool 23.An initial position in connection with this step is indicated at 25. Thefully inserted end portions of the inwardly projecting sanding materialare now in the position indicated in Fig. 4 at 26. In a similar manner,the sanding material is carried about the drum and inserted in theseveral slots I2. The outer end of the sanding material is inserted inthe same slot through which it was originally brought out from theinterior of the drum. This outer end is indicated at 2l, Figs. 1 and 4.

For stretching the sanding material tightly against the working surfaceof the drum and locking it in this position, the wedge member, includingthe plate I5 and the wedge bars 2I, is turned for shifting said barstowards the inner ends of the slots I2. The inwardly projecting portions26 of the sanding strip, as well as the extreme outer end 2l of thesanding strip and the sanding material adjacent thereto (indicated at28, Fig. 1), are all wedged by the bars 2| against the inner wall of thechamber, that is, against the inner surface of the rim. I Il. 'I'heplate I5, on its edge, may be provided with a socket 29 adapted toreceive a rod or tool 30, used as a lever for turning the said plate. Inorder to preclude simultaneous turning of the remainder of the drummember, the plate I 6 may be provided with a similar socket 3| intowhich a tool similar to the rod 3D is inserted for holding the plate I6motionless during rotation of the opposite plate. The rim portions I0and II of the drum member must likewise be kept from turning at thistime and for this purposea pin 32 on the plate I6, projecting into arecess 33 in the rim I0, may be utilized to obviate relative movementbetween these parts.

As already suggested, the sanding drum of this invention would normallybe mounted upon a.

drive shaft I8. Such shaft may be provided with a shoulder 34 (Fig. 2).If the core Il is not of such diameter as to properly t the shaft I8,use may be made of journal or hub members 35, such as the one seen atthe left in Fig. 2. Such hub members are likewise utilized for fittingthe drum to shafts of various sizes. On the opposite side of the drum,as seen in Fig. 2, a cap 3E may be provided, which cap serves as. theexterior means for tightening the core Il in order to keep the supply ofsanding material inside the drum in tightly wound position. For thispurpose, the end of the core I1, which projects upwardly of the plateI5, may be formed with notch members 3l adapted to receive lugs or teeth38 formed on the inner side of the cap 36. The cap is centrallyapertured for reception on the shaft I8 and is likewise provided with arim socket 39, similar to the sockets 29 and 3I, whereby the cap, andconsequently the core associated therewith, may be turned.

'I'he whole unit is pushed on to the drive shaft as far as the shoulder34 against which it may be firmly tightened by use of a nut 4D appliedto the outer threaded end of the shaft I8.

When it is desired to renew the material on the working surface of thedrum, the wedge member is loosened by reverse rotation of the plate I5to permit withdrawal of the of the sanding strip, and thereafter freshsections of sanding material are placed in operative position on thedrum.

In this connection, Fig. 4 clearly brings out an added advantage of thisinvention, namely, the means whereby the totality of the sanding strip,without any waste, may be utilized on the working surface of the drum.The portions of the sanding strip, projecting inwardly of the slots I2,are each substantially equal to the distance between two of the slots.Consequently, these inserted portions of the sanding strip may bewithdrawn and placed against the operating surface of the drum, whilethe previously used sections of the materials may be inserted forperforming the wedging or locking function. In this way, waste of thesanding material is substantially eliminated. The invention is composedof a small number of parts which may be readily produced and assembled,while the operation of positioning and removal of the sanding materialfrom the drum may be effected in a minimum of time.

It is obvious that the distance between the wedge bars 2I and the innerwall of the rim I!! might vary in accordance with the thickness of thesanding or other material to be positioned on the drum, but, in anyevent, the wedging action is positive and as great a Wedging pressure asdesired may be placed upon the ends of the doubled-in portions of thestrip material so that a positive locking of the material in stretchedcondition may be accomplished.

What is claimed is:

1. A sanding drum comprising a drum member formed with an interiorchamber' and a working surface provided with slots communicating withsaid chamber, a wedge member associated with the drum member andcomprising wedge bars mounted for movement in said chamber in proximitywith the slotted portions of the chamber wall, and means for moving thewedge member, a strip of flexible sanding material being adapted to bepositioned about said working surface with portions thereof doubled intosaid slots and projecting into said chamber and said wedge member beingadapted to be moved for wedging the inserted portions vformed with aninterior chamber y `#inserisci end sections of said inwardly doubledstrip porvtions -between said bars and the wall of said chamber wherebyto bind the outer portions of the strip material against the workingsurface of the drum member.

2. A sanding drum comprising a drum member and a Working surfaceprovided with aligned parallel slots communicating with. said chamber, acore mounted in the chamber for axial rotation therein, means forrotating the core, a wedge member associated with the drum member andcomprising wedge bars mounted for unitary rotation in said chamber inproximity with the slotted portions of the Wall of said chamber, saidwedge bars corresponding in number with said slots, and means forrotating the Wedge member, a strip of sanding material being adapted tobe wound on said core and the outer end thereofprojected through one ofsaid slots and passed about-said working surface with portions `ofthestrip. material doubled into said slots and projecting into said`chamber, and said wedge member being adapted to be rotated for causingsaid bars to wedge the ends of said inwardly doubled strip portionsagainst the wall of said chamber whereby the strip material is securelybound againstthe Working surface of l the drum member.

3. A sanding drum comprising a drum member formed with an interiorchamber and a Working i surface provided with slots communicating withsaid chamber, a Wedge member associated with the drum member andcomprising individual Wedge portions mounted for movement in saidchamber in proximity with the slotted portionsof the chamberiwali, andmeans for moving the wedge member, a strip ci flexible sanding mate#rial being adapted to be positioned about said working `surface withportions thereof doubled into said slots and projecting into saidchamber and said wedge member being adaptedl to be moved for Wedging theend sections of said inwardly doubled strip portions between said wedgeportionsand the wall of said'chamber whereby to bind theouter portionsof the strip material l against the working surface of the drum member.

JOHN O. SCHULTE.y

